This invention relates to a switch operating apparatus for operating a disconnector switch of a movable electric device such as a movable transformer, the electric device being carried on a vehicle such as a trailer.
FIGS. 1 and 2 show two commonly used types of switch operating apparatuses mounted on trailers carrying a movable electric device. In the drawings, 1 designates the semi-trailer of a tractor-trailer combination (tractor truck not shown in the drawings). On the trailer 1 are loaded a movable electric device comprising a transformer 2, a circuit breaker 3, a lightning arrestor 5, a cubicle switchboard 6, and a disconnecting switch 4 provided with a switch operating apparatus 7.
In both figures, the disconnecting switch 4 is located near the front of the trailer 1 atop the front luggage carrier 1a. A switch operator 9 controls the disconnecting switch 4 by manually operating the switch operating apparatus 7.
A main difference between these two switch operating apparatuses 7 is that the one shown in FIG. 1 is detachably mounted on the front luggage carrier 1a in a low position close to the ground, while the switch operating apparatus shown in FIG. 2 is permanently mounted on the front luggage carrier 1a in a high position far from the ground.
The switch operating apparatus 7 of FIG. 1 has the advantage that it can be easily and safely operated by an operator 9 standing on the ground, but it has the drawback that it must be disconnected from the disconnecting switch 4 and moved to some other location for storage whenever the trailer 1 is moved. Otherwise, it would interfere with the rear wheels of the tractor truck which tows the trailer 1, particularly when making turns, since the tractor truck fits beneath the front luggage carrier 1a and connects to the connecting portion 1b when it tows the trailer 1.
The switch operating apparatus 7 of FIG. 2, which is permanently mounted high off the ground, has the advantage that it never interferes with the rear wheels of the tractor truck and thus never needs to be moved, but it has the great disadvantage that the operator 9 must stand on some sort of mount 8 in order to operate it. This is not only inconvenient, but it is also unsafe, particularly when working on unlevel ground.